柳林地区多煤层多分支水平井斜井连通工艺

柳林位于鄂尔多斯盆地东缘,区内中煤阶煤层含有丰富的瓦斯气资源,但由于黄土垣地貌沟壑纵横,限制了常规多分支水平井的应用。为了提高煤层气钻井开发效率,创新采用了斜井连通工艺,实现了工程井和排采斜井井口间距10 m的小井场部署,并针对3+4号煤储层与5号煤储层压力相同、适合合采的地质特点,采用多煤层多分支水平井的钻完井技术同时开发3+4和5号煤层,完井下入塑料筛管。目前已经完成4口斜井连通的多煤层多分支水平井,4口井的日产气达到5万m3/d。多煤层多分支水平井钻完井技术成为鄂尔多斯东缘中煤阶煤层气高效开发的示范技术,经济和社会效益显著。

Research on inclined wells connecting technology of multi-coalbed and multiple branches horizontal wells in Liulin District

Liulin is located at the east edge of Erdos Basin, and the medium coalbed in the region contains rich methane gas. But the ravines on loess landform restricted the application of conventional multi-branch horizontal wells. In order to improve development efficiency of the coalbed methane(CBM) drilling, the inclined well connecting technology was innovatively adopted, achieving the goal of small-size wellsite planning where the spacing between the engineering wells and drainage slant hole wellhead is 10 m. In line with that the No. 3+4 coal reservoirs have the same reservoir pressure as No. 5 coal reservoir and are suitable for comingled production, the drilling and completion technique for multi-coalbed multi-branch horizontal wells was innovatively adopted to development No. 3+4 and No. 5 coalbeds at the same time; plastic screen tubes were run in hole after completion. Now a set of multi-coalbed multi-branch horizontal wells have been drilled which connected four inclined wells; the total daily gas production is up to 50 000 m3/d. The drilling and completion technique for multi-coalbed, multi-branch horizontal wells has become the demonstration technology for efficient development of medium coal methane at east edge of Erdos Basin, which achieves remarkable economic and social benefits.